Adapter for vacuum-insulated lines

ABSTRACT

A vacuum adapter for feeding-through vacuum-insulated coolant lines from the surrounding atmosphere into a vacuum processing installation has an intermediate volume which is connected firstly to at least one insulation intermediate space of the vacuum-insulated feed lines and secondly to a vacuum pump. The pump capacity is available at least temporarily for evacuating the insulation intermediate space around the coolant lines.

The invention described hereafter relates to an adapter respectivelyconnector piece to connect a vacuum-insulated line to a vacuumprocessing facility. TECHNICAL BACKGROUND

Vacuum processing facilities are systems in which workpieces orsubstrates are processed respectively treated in a processing room undervacuum conditions, in other words at ambient pressures below theatmospheric pressure. Such systems are known in the state of the art andare used for thermal treatments, coatings, etching processes and manyother processes under reduced pressure conditions.

Many types of vacuum processing facilities use gates (load locks) inorder to use a volume—smaller in comparison with the processing room—forinserting and removing the workpieces in the processing room. Theadvantage is that this smaller volume can be pumped out (evacuated)faster than the processing room, which thus can be maintained for longerbelow a low target pressure. Furthermore, in this manner, the processingroom can more easily be kept free from harmful ambient gases such aswater vapor, volatile organic compounds etc. Some of thesecontaminations can be removed only with difficulty by means of vacuumpumps, which is why the pumping output is often assisted by so-calledMeissner traps. Broadly speaking, a Meissner trap constitutes a cooledcondensation surface for trace gases respectively residual gases,primarily for water vapor under vacuum. They are generally made asconduits of copper or stainless steel that are placed in the vacuumchamber in the form of spirals or flat in a meandering pattern in orderto provide a cooled surface that is as large as possible. Most commonly,commercially available non-CFC coolants or liquid gases (e.g. N₂) can becontemplated as cooling liquids.

The cooling liquid must be directed from a source (e.g. cooling unit,storage tank) into and again out of the vacuum processing chamber bymeans of insulated lines. For this, vacuum-insulated lines are commonlyused in which a flexible line or conduit in an external, vacuum-sealedprotective sleeve is guided. The intermediate space between the coolantline itself and the external sleeve is evacuated so that the heat lossto the environment is minimized. Such vacuum lines are commerciallyavailable, they can be bought ready to use (pre-evacuated). Theintermediate space is often provided with getter material that cancompensate for possible leakages or residual gases. The lines areconnected via vacuum feed-through in the processing chamber wall withthe Meissner trap which, depending on the type of use, can be in theprocessing room or in a gate/lock.

Disadvantages of the State of the Art

The vacuum lines described are sensitive and no reliably vacuum-tightfor a long time. Dismantling and replacing respectively post-evacuatinginvolves a considerable maintenance requirement that negatively impactsthe operating efficiency of vacuum processing facilities especially forindustrial use.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE shows a cross section of a vacuum adapter according to theinvention.

SUMMARY OF THE INVENTION

The present invention should overcome the disadvantages of the state ofthe art. To this effect, a vacuum adapter is proposed that is adaptedfor feeding-through coolant lines in a vacuum processing installation.These lines are discharged to atmosphere in vacuum-insulated feed lines30, 31. An adapter 4 has an intermediate volume 2 that is connected onthe one hand with at least one insulation intermediate space 32, 33 ofthe vacuum-insulated feed lines 30, 31 and on the other hand with avacuum pump 40.

DETAILED DESCRIPTION

The solution according to the present invention consists in a vacuumadapter for connecting a coolant line to a cooling trap of a vacuumprocessing system and simultaneously allows access to the vacuuminsulation of the lines. Via this access, a backing pump that is anywaypresent in the processing system can be connected operatively with thevacuum insulation so that the pump capacity can be used, e.g. with theaid of valves, for evacuating the insulation intermediate space of thefeed lines. This can preferably occur when the system itself temporarilydoes not need this pump capacity. This can happen in a demand-drivenfashion or periodically or permanently for preventative maintenance,preferably under the control e.g. of a routine of the vacuum processingfacility control itself.

In the FIGURE, the vacuum adapter 4 is shown in cross section. It can bemounted on the wall of a processing facility or even integrated therein.The FIGURE shows a vacuum room 1 and hints at the walls of the facilityby means of references 6, 7. An outlined cooling trap 10 is fed by afeed respectively drain line 11, 12. The vacuum adapter 4 comprises avolume 2 that is connected through a pump neck 5 with a vacuum pump 40.The volume 2 is sealed vis-a-vis the vacuum room 1 by means of sealingdevices 13, 14 that allow a passage for the coolant feed lines 12, 11.Ideally, the sealing devices 13, 14 also provide a thermal insulation ofthe line 11, 12 vis-a-vis the adapter 4 respectively the wall connectors6, 7. Reference 13 designates a simple disc that can consist of poorlyheat-conducting material. Detail 14 denotes a bushing that is screwede.g. in the wall of the adapter 4 and by means of the projection intothe volume 2 increases the heat conductivity resistance between thebracket of the line 11 and the wall. The evacuable volume 2 is open tothe insulation intermediate space 32 respectively 33 of the vacuum feedlines 30, 31, and thus enables the latter to evacuate withoutmechanically separating the connections or affecting the vacuum in room1. The vacuum lines 30, 31 consist of an outer sleeve 20, 21 that can beexecuted as a rigid or flexible conduit, corrugated tube, envelope orhose. An inner line 22, 23, represents the coolant line to or from theadapter 4. References 26 and 27 are flange connections of the externalcladding tube 20, 21 to the adapter 4; the connection can alternativelyalso be made by screwing, welding or by means of another suitable typeof connection. The same applies for the outlined flange 24, 25 of theinner line 22, 23. The insulation intermediate space 32, 33 respectivelyits dimensional stability can be ensured by means of the spacingelements (not shown here).

As illustrated in the drawing, the insulation intermediate space 32, 33is connected permanently with a pump option via the inner space 2 of theadapter 4. This ensures the operative performance of the vacuuminsulation of the feed lines 30, 31, and if necessary even controls itfully automatically. Furthermore, a pressure sensor can be installed inthe intermediate volume 2 that displays a drop in the insulation vacuumand provides a warning message before the refrigerating capacity in thevacuum room 1 drops. If a processing step may be stopped or delayed inthis way, it is possible to avoid damages respectively faults in theworkpieces in the room 1.

1. Vacuum assembly structured to be connected to a vacuum room (1) andto coolant lines (11, 12, 22, 23) in vacuum-insulated feed lines (30,31), the vacuum assembly comprising: an adapter (4) with an enclosuredefining an intermediate volume (2), the intermediate volume (2) beingconfigured to fluidly connect to an insulation intermediate space (32,33) of the vacuum-insulated feed lines (30, 31), sealing devices (13,14) disposed at openings in a wall of the enclosure, the sealing devices(13, 14) being adapted to fluidly isolate the intermediate volume (2)from the vacuum room (1), wherein the sealing devices (13, 14) areconfigured to allow the coolant lines (11, 12) to extend through thesealing devices (13, 14), and a pump neck (5) formed in the wall of theenclosure and configured to fluidly communicate with the intermediatevolume (2), the pump neck being adapted to be connected with a vacuumpump (40).
 2. Vacuum assembly according to claim 1, wherein at least oneof the sealing devices is a disc (13) made of a material that hindersheat conduction between the coolant lines (11, 12) and the wall. 3.Vacuum assembly according to claim 1, wherein the enclosure includes apressure sensor in the intermediate volume (2) that displays a drop in apressure of the insulation intermediate space (32, 33).
 4. Vacuumassembly according to claim 1, wherein at least one of the sealingdevices is a bushing (14) made of a material that hinders heatconduction between the coolant lines (11, 12) and the wall.
 5. Vacuumassembly according to claim 1, wherein the sealing devices (13, 14) areconfigured to provide a thermal barrier between the coolant lines (11,12) and the wall of the enclosure by preventing a direct contact betweenthe coolant lines (11, 12) and the wall of the enclosure.
 6. Vacuumprocessing installation with a vacuum room (1) and a vacuum assemblyaccording to claim 1, wherein the vacuum assembly is connected to thevacuum room (1), to coolant lines (11, 12, 22, 23) in vacuum-insulatedfeed lines (30, 31) and to a vacuum pump.
 7. Vacuum processinginstallation according to claim 6, wherein each of the vacuum-insulatedfeed lines (30, 31) includes an outer sleeve (20, 21) in the form of arigid or flexible conduit, a corrugated tube, an envelope or hose, andan inner coolant line (22, 23).
 8. Vacuum processing installationaccording to claim 7, further comprising flange connections (26, 27) forconnecting the outer sleeves (20, 21) to the wall of the enclosure. 9.Vacuum processing installation according to claim 6, wherein the vacuumassembly is mounted on a wall of the vacuum processing installation bymeans of wall connectors (6, 7).
 10. Vacuum processing installationaccording to claim 6, wherein the vacuum pump is a backing pump. 11.Vacuum processing installation according to claim 6, wherein the vacuumassembly is integrated in a wall of the vacuum processing installation.